1. fix core dump when using multi explode_bitmap #7716
2. fix bug that json array extract by json path is wrong #7717
3. fix bug that after lateral view, the null value become non-null value #7718
4. fix bug that lateral view may return error: couldn't resolve slot descriptor 1. #7719
5. fix error result when using lateral view with where predicate #7720
I found some small problems when I read code. So I add some small enhancement.
1. modify PR template. Now the template of PR isn't simple and clear. It's useful to refactor it.
2. some small change (typo, format .....)
A reword suggestion.
Reasons: Before my change, the statement is "If this change need a document change, I have updated the document",
and there is a grammar error in it evidently: "change" cannot be paired with "need".
Either "changes need" or "change need" will be ok at the grammar level.
According to the context, "changes need" will be better.
Now, the statement is "If these changes need document changes, I have updated the document".
1. Rename run-ut.sh to run-be-ut.sh
2. Find all test files from build dir instead of declaring separately in the script
3. Add gtest output to collect the result of unit test.
